1. Field of the Invention
This invention relates to a process for the manufacture of a dipped tire cord fabric made of organic fiber cords including cord joint portions, and more particularly to a process for the manufacture of a dipped tire cord fabric made of organic fiber cords, at least one of which cords including a cord joint portion therein. Particularly, the invention relates to a process for the manufacture of a dipped tire cord fabric made of organic fiber cords including cord joint portions and having a high quality wherein the productivity for connecting ends of two cords to each other is excellent, and a size of the joint portion is thinner than the conventional one and becomes approximately equal to a diameter of a non-connected portion of the cord and a tensile strength of the joint portion is high and the fabric is particularly suitable as a reinforcing member for pneumatic tires or conveyor belts.
2. Description of Related Art
The organic fiber cord used as a reinforcing member for the conveyor belt or the pneumatic tire is so-called two or three strand cord formed by subjecting two or more bundles of organic multifilaments to cable twisting and ply twisting. In case of producing this type of the organic fiber cord before dipping, it is unavoidable to vary lengths of the resulting organic fiber cords and also the organic fiber cord having a very long length is sometimes required, so that it is necessary to conduct work or operation of connecting the organic fiber cords to each other.
As general means for connecting the organic fiber cords by hand labor, there is a sewing connection through an electric sewing machine. In such a sewing connection, end portions Ae, Be of two different cords A, B are sewn by means of the electric sewing machine at a state of simply overlapping these end portions with each other as shown in FIG. 5, so that even if the sewing work is conducted more carefully, free end threads not sewn always come out at both ends of a knot portion C between the cords.
These free end threads are required to deliberately cut off from the knot portion by means of scissors or the like. In this case, there is caused a problem that the cords A and B existing in the knot portion are injured or a part of the filaments in these cords is cut off. And also, there is caused an inconvenience that during the manufacture of the tire cord fabric, the free end threads of the knot portion C are caught on other cords adjacent thereto, a dropper pin, a held wire and the like to cause a temporary stop of operation in an apparatus for the manufacture of the tire cord fabric or the cord breaking-up. Furthermore, since the electric sewing machine itself is big, there are caused secondary inconveniences that it is difficult to move the electric sewing machine in a factory having a limited space, and a power feeding cable for the electric sewing machine becomes cumbersome and the like.
In addition to the above means, there is a method of connecting the cords with an apparatus called as a knotter. According to this method, the connecting time required for the completion of, for example, a single joint cord is required to be about five minutes, which is inefficient, and also the untwisting work is required after the connection through the knotter. The latter work tends to depend on the sixth sense and the gist by a skilled worker. Therefore, this method is at variance with the reality.
In order to solve the above problems in the connection between mutual cords, JP-T-6-505,222 discloses a method of connecting ends of two assemblages (cords) wherein an end of one of the assemblages (two or three strand cord) each made of two or more multifilament threads is untwisted to separate the threads at such an end, and an end of the other assemblage is untwisted to separate the threads at such an end likewise the above case, and a pair of these assemblages are placed side by side and also untwisted thread parts in each of the assemblages are placed side by side to obtain junction regions shifted axially from each other, and filaments of the two threads in each junction region are assembled together by air splicing.
Since this connection method need not use the electric sewing machine, the knotter or the like, it is possible to shorten the connecting time and there is not feared the generation of the free end filaments at the knot portion. And also, the junction regions are shifted axially from each other and dispersed in each of the assemblages, so that it is sure to have a merit capable of making the bulge of the knot portion small.
In this method, however, it is necessary that the two or more strand cord is specially separated into the multifilament threads, and such a separation is kept so as not to return it, and the untwisting is carried out every the multifilament thread, and the twisting operation is carried out every the multifilament thread after the completion of the connecting work, so that the method takes labor and requires 2-3 minutes for completing a single joint cord and hence the operability for connecting the cords still stands improvement. For this end, it should be noticed to adopt the connection between the cords as a dipped tire cord fabric made of organic fiber cords without sticking only the connection between the two cords.